In the Montreal dressing room in Tampa following a 4-1 loss in Game 6 of the Eastern Conference Second Round, Canadiens defenseman P.K. Subban was upset and wasn't hiding it.

Subban spoke at length about the frustration he felt with the Canadiens' inability to score at the most important time of the season and the urgency required to take advantage of their window to end the longest Stanley Cup drought in their history.

It was not a time of joy. Not for Subban nor his teammates, and definitely not back in Montreal.

Nobody knew then how important that loss would turn out to be. Subban didn't. The residents of Montreal didn't. Least of all, Marie-Josée Gariépy didn't.

Gariépy is president of the Montreal Children's Hospital Foundation, and the day after the May 12 season-ending loss she was continuing preparations for The Ball for the Children's, a major fundraising event scheduled for May 21.

A week before the event, Gariépy received a phone call telling her Subban was interested in not only attending the ball, but holding a live auction to help raise funds, something he couldn't have done had the Canadiens advanced to the Eastern Conference Final.

"We changed the whole scenario of the evening because he wanted to do a live auction, and that's something we never do at the ball," Gariépy said. "The evening was planned, as you can imagine a week before the event.

"But I still have goose bumps when I think about that night. It was quite an evening."

It had a profound effect on the foundation, the hospital and the city, laying the groundwork for the seven-year, $10 million commitment to the Montreal Children's Hospital made by Subban and his foundation four months later.

It is one part of the increased philanthropy by Subban in 2015.

"The opportunity was brought to me now, and I felt the need to want to do it now," he said. "That's not something that someone can tell you. You need to know yourself."

Subban arrived at the ball with his former minor hockey coach, Martin Ross, who Subban has known since he was 7 years old and is now his manager. Gariépy recalled Subban telling the crowd he would sell one or two of his Canadiens jerseys for $1,000 each, creating a buzz in the room.

Then he brought out 100 jerseys.

"They were all sold in five minutes," Gariépy said. "Actually, we didn't have enough of them. … When you have an event with 600 people, you rarely see 100 people buying something that expensive for $1,000. It was the right crowd, but still.

"He signed every single jersey individually after and took a picture with every single donor that had purchased a jersey."

Subban raised $100,000 for the foundation in five minutes and another $38,200 auctioning other items, including a chance to come to a Canadiens game and have a meet-and-greet with him afterward.

Gariépy was blown away. But the best was yet to come.

Ross approached Gariépy and told her Subban would like to speak to her for 30 minutes at the end of the evening.

"He wants to do something for charity and he wants to choose a cause," Gariépy remembered Ross telling her. "So you should make your pitch."

That 30-minute pitch became 90 minutes, and the idea for Subban's donation was born.

"At one point during that conversation I asked him, because I always try to understand what are the motivations of our donors, so I said to him, 'Is visibility something that is important to you? Would you like to see your name somewhere in the hospital?' Then I saw his eyes got really big," Gariépy said. "Now that I know P.K., I know that was a very stupid question."

Various locations around the hospital were discussed until Gariépy mentioned the hospital's atrium, a large, bright, open space that welcomes people entering the back entrance of the building.

Subban's eyes got even bigger.

"Then he said, 'Well, what's the price tag on that?' I said $10 million. Big silence," Gariépy said. "Then he said, 'Yeah. Let me think about that.' So we spent the whole summer going back and forth. He came to the hospital and he got really excited when he saw the space."

Today, that space is called the P.K. Subban Atrium, but that is only a part of what Subban does for the hospital. He sits on the foundation's board of directors, visits so often he's been given a doctor's parking pass and, perhaps most importantly, has immeasurably increased its visibility.

Gariépy said the file of press clippings from the news conference announcing Subban's donation on Sept. 16 is 4 inches thick, with stories from as far away as Australia and Asia.

"The only word that comes to mind is 'transformational.' That gift has been transformational for all kinds of reasons," Gariépy said. "The money of course, because we're talking about a lot of money, but it's also P.K. himself; his brand, his personality, what he's bringing to the kids as an amazing role model. Every time he shows up, I'm telling you, people are so excited to see him, and he's happy.

"There's nothing about P.K. that is fake. This guy is not fake at all. This guy is truly authentic."

Subban turned 26 the day after that playoff loss to the Lightning, but his decision to have a greater impact off the ice than he does on it came long before.

He felt he needed to be strategic about his plans and capture people while he has their attention, even if it means shrugging off a bitter professional disappointment to make a last-minute, "transformational" visit to a fundraiser.

"I have the ability as of right now to encourage other people to get involved," Subban said. "I may not always have that ability to get people to donate money and join my charity or my foundation or my events. But right now I do, so I'm trying to capitalize on that. Who knows? Hopefully I have that for the rest of my life, but why not do it now?"